Sarcoidosis is a non-caseating epithelioid granulomatous multisystem disorder that most commonly affects the lungs, heart, skin, and central nervous system. [1] Primary localized cutaneous amyloidosis (PLCA) shows deposition of amyloid in previously apparently normal skin, with no evidence of deposits occurring in internal organs. PLCA is classified into macular and papular forms, and a rare nodular form (NPLCA). [2] Here, we describe the first case of NPLCA in a patient with pulmonary sarcoidosis (PS).

A 67-year-old Japanese woman was referred to our department for diagnosis of pink to yellowish nodules on both sides of her lower jaw [Figure 1]a. The nodule on the left lower jaw had a 5-year history and that on the right had a 2-year history with gradual enlargement. Eleven years previously, at age 56, she was diagnosed with PS based on mediastinal lymph node biopsy. Subsequent observation of the clinical course had continued at a general hospital. Laboratory tests, including complete blood cell count, urinalysis, angiotensin-converting enzyme level, and liver and kidney functions, were within normal limits. Pulmonary function tests and electrocardiogram data were also within normal limits. Computed tomography scans of the chest and abdomen showed swollen hilar and mediastinal lymph nodes, consistent with sarcoidosis [Figure 1]c, but no other findings related to sarcoidosis or systemic amyloidosis were detected.

Figure 1: (a) Photographs of the left lower jaw at the first visit showed a pink to yellowish nodule measuring 30 mm. (b) At 18 months after starting treatment, the lesion had flattened, but still remained. (c) A CT study showed a swollen hilar lymph node (red arrows), consistent with sarcoidosis

Skin-punch biopsy (4 mm) was performed for the nodule on the left lower jaw. The biopsy specimen showed extensive deposition of pale eosinophilic amorphous material through the entire dermis into the fatty tissue, with dense infiltration of plasma cells [Figure 2]a. The amorphous material was positive for both Congo red and Dylon [Figure 2]b. We diagnosed this case as NPLCA occurring in a patient with PS. Topical application of betamethasone valerate 0.12% foam was started. A year and a half after starting the treatment, the lesion flattened, but the yellow plaques still remain [Figure 1]b. PS has been stable without treatment.

NPLCA is considered to be a cutaneous plasmacytoma, and the lesion appears as single or multiple pink to yellowish-brown nodules on the face, extremities, trunk, or genitals. [3] Of all cases of NPLCA, 7% progresses to systemic amyloidosis. [3] The etiopathogenesis of amyloid deposition in NPLCA has yet to be clearly elucidated, but the development of a clone of plasma cells might be responsible for producing amyloid. [3],[4] The etiology of sarcoidosis also remains unknown, but might be related to environmental, immunologic, infectious, and genetic factors. [1] To date, coincident sarcoidosis and systemic or secondary amyloidosis have been sporadically reported. [4] Dahdah et al. [5] also reported a case of co-existing macular form of PLCA and sarcoidosis. However, to our knowledge, this report is the first description of concomitant appearance of NPLCA and PS. We cannot state with certainty whether the occurrence of these two diseases was associated or independent, but Dahdah et al. [5] suggested that a subset of PLCA patients, especially those with extensive or atypical involvement, may have associated immune disorders. In our case, NPLCA and PS have been stable without subjective symptoms. However, localized cutaneous AL amyloidosis which might have a similar presentation may have to be ruled out, and progression to systemic amyloidosis and severe PS is possible, and continuous and careful observation of the clinical course is required.